CN1542757A - Optical disk and optical disk apparatus - Google Patents

Abstract

In an optical disk (1) of the invention composed of two substrates (1a, 1b) bonded to each other, the level of double refraction is set to 60 nm or less in a read-only disk, to 60 nm or less in a write-once type disk, and to 40 nm or less in a rewritable type disk, respectively.

Description

CD and compact disk equipment

Technical field

The present invention relates to a kind of laser beam of utilizing is recorded in information on the information recording carrier, and from the compact disk equipment of information recording carrier information reproduction, as the CD of information recording carrier, described CD can stably obtain C/N than higher signal, and a kind of compact disk equipment.

Background technology

CD has various structures, for example CD and DVD-ROM the representative CD-ROM, write-once (write-once) the type CD of CD-R and DVD-R representative, but rewriting type optical disk of the external memory storage of computing machine and the representative of recoding/reproduction video disc or the like.

Recently, require to increase the capacity of CD, so that the rapid increase of reply information and the required recording capacity of broadcasting equipment.Therefore, carried out various researchs, with the wavelength (reducing to assemble the diameter of luminous point) that reduces laser beam with utilize super-resolution technique, and the stamper manufacturing technology of check electron beam exposure etc., so that reduce track space and mark pit spacing.

Now, matrix by molded 0.6 millimeters thick of injection moulding polycarbonate resin, on described matrix, form reflectance coating and recording film, utilize ultraviolet curable resin (below be called the UV resin) etc. bonding mutually subsequently, form the widely used dvd standard CD of 1.2 millimeters of thickness two matrixes.

DVD-RAM is for example by commercialization, so that deal with the requirement of at least two hours MPEG2 image of record on the one side of the CD of 12 centimetres of diameters, DVD-RAM has the memory capacity of single face 4.7GB, the line density of the track density of 0.74 micron/track and 0.267 micron/.In addition, be used to write down or the wavelength of the light beam of information reproduction is 650 nanometers, the numerical aperture that is installed in the object lens in the optical head is 0.6.

Incidentally, when forming thin resin CD by injection moulding, when being difficult to eliminate fully, remain in the optical anisotropy that the influence of the mechanical stress in the matrix causes by molding optical disks.Because known birefringence (double refraction) causes by optical anisotropy, phase delay results from birefringence, can produce the problem that the intensity of reproducing signal is attenuated in CD thus.

That is, when having predetermined wavelength and along the polarization of predetermined direction, and be radiated at light beam on the CD and transmit by CD and when CD penetrates, owing to birefringent influence, the intensity that can be used as the light beam of reproducing signal is lowered.Thereby in above-mentioned dvd standard CD, the birefringent upper limit is configured to 100 nanometers.

Now, propose the long light beam of radiothermy, for example utilized 405 nanometer light beams to increase recording density.In this case, even birefringence has identical numerical value, owing to reducing of light beam wavelength, the amplitude of reproducing signal is further reduced.

The open No.2002-304770 of Japanese patent application KOKAI relates to the birefringent method of CD that a kind of regulation is used the light beam of wavelength 400 nanometers, and propose along the CD sense of rotation, in a week of CD, birefringent variable quantity is arranged to ± 20nmpp or littler.

In addition, the open No.2000-67468 report of Japanese patent application KOKAI is bonded in system on the substrate of recorded information to transparent membrane by adopting, and in optical record medium, 20 nanometers is arranged in the birefringence of transparent membrane.

As mentioned above, when the light beam that uses the short wavelength improves the recording capacity of CD, produce the problem that the amplitude from the reproducing signal of CD is lowered, the information regeneration instability.

The birefringent numerical value of stipulating among the open No.2002-304770 of Japanese patent application KOKAI is actually the numerical value that is adhered to the single transparent sheet on the supporting substrates, thereby this numerical value is not to comprise by injection moulding in the molded matrix of design transfer on it, the meeting that must consider causes the complete characteristic of serious problems, for example the numerical value of the thickness of the curling of design transfer, matrix, matrix etc.

The birefringent numerical value of stipulating among the open No.2000-67468 of Japanese patent application KOKAI also is to pass through bonding coat, be adhered to the numerical value of the single film on the matrix surface, this numerical value is not to comprise by injection moulding in the molded matrix of design transfer on it, the meeting that must consider causes the complete characteristic of serious problems, for example the numerical value of the thickness of the curling of design transfer, matrix, matrix etc.

As mentioned above, though in each patent disclosure or they arbitrary among disclosed numerical value be satisfied, the amplitude that does not still have to solve the reproducing signal that obtains from CD is lowered and the information regeneration problem of unstable.

The injection moulding mould is Unitarily molded to comprise high density pit and groove when utilizing, and when using the CD of light beam of 405 nano wave lengths, compares with the dvd standard CD of the light beam that utilizes 650 nano wave lengths, requires stricter transfer characteristics.Therefore, when the birefringent numerical value of regulation, also must consider the value of the amplitude of reproducing signal.

Summary of the invention

According to one embodiment of present invention, a kind of CD is provided, described CD comprises by the molded molded matrix that forms of injection moulding, and has a transfer information flag thereon, on described CD, form and utilize 600 nanometers or the laser beam of small wavelength more, can only write down the recording film of primary information, and can be with respect to its record and information reproduction, perhaps on described CD, form reflectance coating, so that from optical disc replay information, wherein when utilizing twice when measuring, the value of the birefringence component in the whole zone of CD is ± 60 nanometers or littler.

According to one embodiment of present invention, a kind of compact disk equipment is provided, described compact disk equipment can form relatively thereon and utilize 600 nanometers or the laser beam of small wavelength more, can only write down the CD of the recording film of primary information, record and information reproduction, perhaps described compact disk equipment can form the optical disc replay information of reflectance coating from it, and wherein when utilizing twice when measuring, the value of the birefringence component in the whole zone of CD is ± 60 nanometers or littler.

According to one embodiment of present invention, a kind of CD is provided, described CD comprises by the molded molded matrix that forms of injection moulding, and has a transfer information flag thereon, on described CD, form the recording film that can write down with erasure information, and utilize 600 nanometers or the laser beam of small wavelength more, can be on described CD recorded information or from described optical disc replay information, wherein when utilizing twice when measuring, the value of the birefringence component in the whole zone of CD is ± 40 nanometers or littler.

According to one embodiment of present invention, a kind of compact disk equipment is provided, described compact disk equipment can form relatively thereon and utilize 600 nanometers or the laser beam of small wavelength more, can write down CD with the recording film of erasure information, record and information reproduction, wherein when utilizing twice when measuring, the value of the birefringence component in the whole zone of CD is ± 40 nanometers or littler.

Description of drawings

The accompanying drawing that is contained in the instructions and constitutes an instructions part is for example understood embodiments of the invention, and and the general remark that provides above and the detailed description one of embodiment given below be used from explanation principle of the present invention.

Figure 1A～1E is the synoptic diagram that the process of CD is produced in expression;

Fig. 2 A～2C is the synoptic diagram that expression is positioned at the process afterwards of process shown in Fig. 1 E;

Fig. 3 is that expression utilizes the process shown in Figure 1A～1E and Fig. 2 A～2C, the synoptic diagram of the example of the cross-sectional structure of the CD of formation;

Fig. 4 has represented the structure of optical head;

Fig. 5 has represented the schematic construction of compact disk equipment;

Fig. 6 is the circuit diagram that expression input part and signal are determined the schematic construction of circuit;

Fig. 7 is the block scheme of the schematic construction of expression level clipped signal treatment circuit and PRML signal processing circuit;

Fig. 8 A～8F is the signal waveform of major part of expression level clipped signal treatment circuit and the synoptic diagram of data value;

Fig. 9 A～9G is the signal waveform of major part of expression PRML signal processing circuit and the synoptic diagram of digital value;

Figure 10 A～10C is the synoptic diagram of the decoding processing of explanation ML demoder execution;

Figure 11 has represented the example of structure of the recording film of recording disk;

Figure 12 has represented the modulated laser waveform that is used to write down;

Figure 13 is the synoptic diagram of the example of the data structure of Lead-In Area in the explanation read-only optical disc;

Figure 14 A～14C is the structure of Lead-In Area, data field and data leading-out zone of the double-deck read-only optical disc of explanation and the synoptic diagram of data structure;

Figure 15 is the synoptic diagram of the mechanical dimension of CD shown in the key diagram 3;

Figure 16 is the synoptic diagram of record data density in each zone of explanation read-only optical disc;

Figure 17 is the synoptic diagram of example of data structure of the control data zone of the various CDs of explanation;

Figure 18 is the synoptic diagram of content of information in the physical format of explanation read-only optical disc;

Figure 19 is shown in explanation Figure 18 in the physical format, the synoptic diagram of the example of the content of information (writing the type of standard and the type of each several part);

Figure 20 is shown in explanation Figure 18 in the physical format, the synoptic diagram of the example of the content of information (disc size and CD maximum transfer speed);

Figure 21 is shown in explanation Figure 18 in the physical format, the synoptic diagram of the example of the content of information (compact disk structure);

Figure 22 is shown in explanation Figure 18 in the physical format, the synoptic diagram of the example of the content of information (recording density);

Figure 23 is that the synoptic diagram of the content of information is distributed in the data field in all kinds of CDs of explanation;

Figure 24 is that the synoptic diagram of the content (BCA descriptor) of information is distributed in the data field shown in explanation Figure 23;

Figure 25 is the synoptic diagram of the record data density in each zone of declare record/reproduction (but rewriting type) CD;

Figure 26 is data importing district and the structure of system's Lead-In Area and the synoptic diagram of data structure of explanation CD-RW;

Figure 27 is the synoptic diagram of the structure of the bonding pad between explanation data importing district and the system's Lead-In Area;

Figure 28 is data importing district and the structure of system's Lead-In Area and the synoptic diagram of data structure of explanation Write-once optical disc;

Figure 29 is the synoptic diagram of explanation another example (example of input/signal evaluation circuit that is used for the signal of playback system Lead-In Area) of comprising the signal reproduction circuit of PRML signal processing circuit;

Figure 30 is the synoptic diagram of the limiter shown in explanation Figure 29;

Figure 31 is the synoptic diagram of example of the input/signal evaluation circuit of the explanation signal that is used for the playback system Lead-In Area;

Figure 32 is the synoptic diagram that the example of the Viterbi decoder that is used for the signal evaluation circuit shown in Figure 31 is described;

Figure 33 is the synoptic diagram of example calculation of the path metric of description time t;

Figure 34 is the synoptic diagram of the example of explanation path memory;

Figure 35 is the synoptic diagram of the example of structure of explanation I/O and path memory cell;

Figure 36 is the synoptic diagram of explanation from the output of final path memory cell.

Embodiment

Below with reference to accompanying drawing, describe embodiments of the invention in detail.

Fig. 1 and 2 is the synoptic diagram that the process of the suitable CD of embodiments of the invention is produced in the order explanation.

At first, as shown in Figure 1A, prepare 220 millimeters of diameters, the glass plate that thickness is 6 millimeters after its surface is polished to predetermined surface smooth finish and cleans, obtains glass substrate 101.

Next, as shown in Figure 1B, photoresist 102 is coated on the surface of glass substrate 101, afterwards, as shown in Fig. 1 C, the gas laser of utilization use wavelength 351 nanometers makes pattern 103 exposures of being made up of guiding groove (recessed-convex portion), pit etc. as the base plate exposure machine of light source.

Subsequently, utilize alkaline developer that the glass substrate 101 of exposure is developed,, obtain the pattern 104 that constitutes by pit etc., as shown in Fig. 1 D so that eliminate the undeveloped portion of photoresist.

Subsequently, as shown in Fig. 1 E, plating Ni or analog on glass substrate 101, by the Ni coating that scales off from glass substrate 101, acquisition pattern 104 has been transferred to the pressing mold 105 on it.

As shown in Fig. 2 A, pressing mold 105 is placed on the injection (mo(u)lding) machine 201, utilize pressing mold 105 as mould, carry out injection moulding, thereby obtain the resin mold pressing plate, be transferred on the described resin mold pressing plate (the first matrix 1a or the second matrix 1b of the CD that the resin mold pressing plate illustrates corresponding to the following Fig. 3 of utilization) by the predetermined pattern of compositions such as guide recess (recessed-convex portion, i.e. convex ridge and groove), pit.Notice that in many cases, matrix (resin mold pressing plate 1a or 1b) is formed by polycarbonate.

Subsequently, as shown in Fig. 2 B, utilize sputtering equipment to form metal or alloy film 2, perhaps, utilize spinner coated dye film 2 according to the application of CD and the type of first and second matrix.For example, when CD is DVD-ROM, form Al or Ag reflectance coating 2, when CD is DVD-RAM, form multilayer recording film 2.Pseudo-(dummy) substrate also is used as described matrix, and pseudo-substrate is a kind of flat board, is formed with arbitrary graphic pattern, metal or alloy film and dye film 2 on it.

Subsequently, as shown in Fig. 2 C, matrix (1a or 1b) is installed on the rotating disk of spinner (unspecified), the UV cured resin (not shown) of solidified by ultraviolet ray radiation is coated on the matrix, as bonding agent.Subsequently, before second matrix (1b) in different process of preparing was placed on the matrix (1a), and shone (unspecified) with ultraviolet ray (UV), thereby these two matrixes (1a and 1b) are bonded together.

Note, when molded matrix 1a and 1b, optimize temperature, the pressure when injecting resin material, cool time, mould velocity of separation of the splitting die period of the day from 11 p.m. to 1 a.m and so on parameter such as resin material and pressing mold (mould) 5.By above-mentioned optimization, such as the design transfer speciality of each matrix (1a and 1b), the curling of single matrix, birefringent value in the matrix, the class feature of the thickness of matrix is configured to predetermined value.

Incidentally, when the process mold pressing resin that utilizes with reference to Figure 1A～1E explanation, when obtaining matrix, if in molded matrix, design transfer to matrix the time, is difficult to eliminate fully the optical anisotropy that is caused by the influence of the residual mechanical stresses in the matrix.

As everyone knows, birefringence causes by optical anisotropy, and is therefore when from optical disc replay information, as described below, forms various devices to guarantee the amplitude of signal.

Fig. 5 is that expression is recorded in information on the CD illustrated in fig. 3, and reproduces the synoptic diagram of example of the compact disk equipment of the information on this CD that is recorded in.

Compact disk equipment 20 is information, and promptly data are recorded on the CD 1, perhaps reproduces the data that are recorded on the CD 1, and CD 1 is an information recording carrier.

Compact disk equipment 20 comprises optical pickup apparatus (optical head) 21, reception is from CD 1 laser light reflected bundle, and the output value is corresponding to the detecting signal unit 22 of the electric current of laser beam intensity, level amplitude limit (slice) signal processing circuit 23, PRML (partial response and PRML) signal processing circuit 24, signal is determined circuit 25, Drive and Control Circuit 26, error correction unit 27, host device interface 28, modulator 29, write compensating circuit 30, write driver 31, servo controller 32, spindle motor 33 etc.Note therefore omitting detailed description thereof because error correction circuit 27, host device interface 28 and modulator 29 are not the directly related assemblies of embodiments of the invention.

Optical pickup apparatus 21 shown in Fig. 5 comprises can send predetermined wavelength, the semiconductor Laser device of the laser beam of 450 nano wave lengths (light beam) (below abbreviate laser diode as) 11 for example, the laser beam of sending from laser diode 11 is converged to the object lens 12 on the recording surface of CD 1, reception is from the light (light beam) of the record surface reflection of CD 1, and the photodetector 13 of the electric current of output and catoptrical intensity correspondence (detecting signal unit 22) etc., as shown in Figure 4.

CD 1 is positioned on the clamper (not shown) of spindle motor 33, and is rotated by spindle motor 33, thereby the speed in the whole zone of the speed of the pit of the indication information of unit length (mark) string (train) and CD 1 is identical.

Polarization spectroscope 14 and delayer (quarter wave plate) 15 is placed between object lens 12 and the laser diode 11.Polarization spectroscope 14 utilizes the reflection and the transmission of the direction of the plane of polarization that depends on laser beam, separation is from the light of laser diode 11 directive CDs 1 with at the light of the record surface reflection of CD 1, and delayer (quarter wave plate) 15 is adjusted from the light of laser diode 11 directive CDs 1 and the isolation between the light that the record surface of CD 1 reflects.

The write driver 31 that laser diode 11 has the laser driver (not shown) and is attached thereto.Laser driver makes laser diode 11 outputs have the laser beam of predetermined strength, and whether the existence of the information that write driver 31 bases will write down, changes from the intensity of laser beam of laser diode 11 outputs.

Pass through object lens 12 from the laser beam of laser diode 11 outputs, converged on the record surface of CD 1.

When CD 1 is in the time of can only writing down the CD of primary information, when recorded information, utilize the laser beam of assembling on CD 1, to form pit (mark) string.When but CD 1 is a recorded information, and can wipe the CD of message the time, when recorded information, changes the phase place of CD 1, and on CD 1, form pit (mark) string.Notice that pit (mark) string utilizes the interval between the mark and the length of each mark, expression information.

When from CD 1 information reproduction, according to the existence of pit (mark) string whether, change the polarization direction of CD 1 laser light reflected bundle.

Laser diode 11 is according to writing the indication (power) that compensating circuit 30 is provided with, and output intensity is corresponding to the laser beam of the value of the laser drive current of supplying with from write driver 31.For example, output device is useful on the reproducing power that obtains reproducing signal, is used for the laser beam of one of any intensity of the erase power of the recording power of recorded information and erasure information.

As shown in Figure 6, the detecting signal unit 22 of optical pickup apparatus 21 (photodetector 13) comprises current/voltage transducer (amplifier) 41a, 41b, 41c, 41d, totalizer 42a, totalizer 42b, subtracter 43 etc.Current/ voltage transducer 41a, 41b, 41c, 41d (are divided into four zones to any surveyed area from the photodetector 13 of the photodetector that serves as detection laser beam this example, and, represent the relevant detection zone with 13a, 13b, 13c and 13d according to clockwise direction from upper left detection zone 13a) each detection signal (Ia, Ib, Ic, Id) of supplying with converts voltage signal to from current signal.Totalizer 42a is the signal plus from amplifier 41a and 41b, and totalizer 42b is the signal plus from amplifier 41c and 41d, and 43 signals from totalizer 42a of subtracter deduct the signal from totalizer 42b.

From the signal of subtracter 43, promptly the signal from detecting signal unit 22 outputs is provided for level clipped signal treatment circuit 23 and the PRML signal processing circuit 24 of reproducing data.

As shown in Figure 7, level clipped signal treatment circuit 23 comprises AGC (automatic gain control) amplifier 51, totalizer 52, balanced device 53, level clip detector 54, PLL circuit 55, RLL detuner 56, AGC controller 57, offset controller 58 etc.

Proofread and correct according to control signal by AGC amplifier 51 from the level (by the light from CD 1 reflection is carried out the output that opto-electronic conversion obtains) of detecting signal unit 22 signal supplied, and be provided for totalizer 52 from AGC controller 57.

Totalizer 52 has been controlled its gain by AGC amplifier 51 signal adds the shifted signal from offset controller 58, and is provided for balanced device 53.

The signal that 53 pairs of totalizers 52 of balanced device have added shifted signal carries out wave shape equalization (processing), be the threshold value that before had been provided with respect to the waveform (reproduction waveform) of reproducing signal and the intersection point consistent with the center of window (perhaps near unanimity) of equalizing signal thereby make, this signal is provided for level clip detector 54, AGC controller 57 and offset controller 58 subsequently.

Level clip detector 54 is according to the channel clock from PLL circuit 55, detection is from the equalized waveform of balanced device 53 and the intersection point of threshold value, when in window, detecting intersection point, provide binary data " 1 " to RLL detuner 56, when in window, not detecting intersection point, provide binary data " 0 " to RLL detuner 56.

PLL circuit 55 produces channel clock according to the signal from level clip detector 54, and channel clock is offered RLL detuner 56.

RLL detuner 56 is according to the RLL code, to the binary data demodulation from level clip detector 54.

AGC controller 57 by the equalized waveform output of balanced device 53 equilibriums, is provided with the correcting value in the AGC amplifier 51 according to its waveform.

Offset controller 58 is offering totalizer 52 based on the off-set value from the even waveform of balanced device 53 outputs.

Utilize Fig. 8 A-8G below, the example of waveform limiter system (it is the signal processing system of being carried out by level clipped signal treatment circuit 23) is described.Fig. 8 A represents record data, Fig. 8 B represents wave recording, and Fig. 8 C represents the position relation between pit and the laser beam, and Fig. 8 D represents to reproduce waveform (it is the output from detecting signal unit 22), Fig. 8 E represents equalized waveform, and Fig. 8 F represents to detect the intersection point of binary data.Wave recording according to corresponding to the NRZI of record data (Fig. 8 A) (oppositely non-return-to-zero) form (Fig. 8 B) is pre-formed pit (mark) string as shown in Figure 8 on CD 1, record data are the information that will write down.

When reproduction is recorded in information on the CD, with the form of the beam spot shown in the oblique line among Fig. 8 C, from the laser diode 11 of pick-up 21, the reproduction laser light beam on pit (mark) string of CD 1.By this operation, can obtain whether to exist according to pit, and the reflection lasering beam of the direction of polarization light in change reflectivity or the beam spot.The laser light reflected bundle is received by the detecting signal unit shown in Fig. 5 22, and the experience signal Processing, thus the information of playback record on CD 1.That is, can obtain and be recorded in the reproducing signal of the information correspondence on the CD 1 according to by by 13 pairs of outputs that obtain from CD 1 laser light reflected Shu Jinhang opto-electronic conversion of the photodetector shown in Fig. 4.

Because the characteristic of recording/reproducing system, not the square waveform with the wave recording that utilizes Fig. 8 B explanation as the front, but with the waveform (reproduction waveform) of the blunt waveform formation as shown in Fig. 8 D from the reproducing signal of detecting signal unit 22 (photodetector 13).

The waveform (reproduction waveform) of the reproducing signal shown in 53 couples of Fig. 8 D of balanced device carries out wave shape equalization (processing), thereby make before the threshold value (representing) that the waveform (reproduction waveform) with respect to reproducing signal is provided with and the intersection point consistent with the center of window (perhaps approaching unanimity) of equalizing signal, as shown in Fig. 8 E by the dot-and-dash line among Fig. 8 F.Specifically, the high fdrequency component of reproducing signal is exaggerated.

When level clip detector 54 detects the intersection point of equalized waveform and threshold value in window, the waveform (equalized waveform) that has experienced the reproducing signal of equilibrium treatment is changed into " 1 " by scale-of-two, as shown in Fig. 8 F, when not detecting intersection point therein, the waveform of described reproducing signal (equalized waveform) is changed into " 0 " by scale-of-two.

Therefore, the restituted signal that obtains by the binary data demodulation that level clip detector 54 is obtained from 56 outputs of RLL detuner.

As shown in Figure 7, PRML signal processing circuit 24 comprises AGC amplifier 61, totalizer 62, A/D converter 63, linear equalizer (balanced device) 64, ML demoder (Viterbi (Viterbi) demoder) 65, RLL detuner 66, PLL circuit 67, AGC controller 68, offset controller 69 etc.

AGC amplifier 61 is proofreaied and correct from the level of detecting signal unit 22 signal supplied (by the light from CD 1 reflection is carried out the output that opto-electronic conversion obtains), and is provided it to totalizer 62 according to the control signal from AGC controller 68.

Totalizer 62 adds its gain in the shifted signal by the signal of AGC amplifier 61 controls, and provides it to A/D converter 63.

By according to channel clock from PLL circuit 67, be converted into discrete time and discrete amplitudes value sequence (series), A/D converter 63 becomes digital signal to the conversion of signals that totalizer 62 has added shifted signal, and provides it to linear equalizer 64.

Equilibrium treatment is carried out in the 64 pairs of digital signals outputs from A/D converter 63 of linear equalizer that comprise FIR wave filter (transversal filter) etc., thereby the waveform of digital signal has the PR (1 of the waveform (reproduction waveform) with respect to reproducing signal, 1) characteristic, this digital signal are provided for ML demoder 65, PLL circuit 67, AGC controller 68 and offset controller 69.

65 pairs of equalized waveforms from balanced device 64 of ML demoder are decoded, and provide it to RLL detuner 66 with the form of binary data.Viterbi decoder can be used as ML demoder 65.

RLL detuner 66 is according to the RLL code, to the decoding binary data demodulation from 65 outputs of ML demoder.

PLL circuit 67 produces channel clock according to the equalized waveform from linear equalizer 64 outputs, and channel clock is offered A/D converter 63.That is, PLL circuit 67 converts the difference between the range value of PR equalized waveform and its desirable range value to and differs, thereby recovers (demodulation) channel clock.

AGC controller 68 is provided with the correcting value (gain control level) in the AGC amplifier 61 according to the equalized waveform from balanced device 64 outputs.

Offset controller 69 is provided with and will offers the off-set value of totalizer 62 according to the equalized waveform from balanced device 64 outputs.

Below, utilize Fig. 9 A-9G, the signal processing system that PRML signal processing circuit 24 is carried out is described.Fig. 9 A represents record data, and Fig. 9 B represents wave recording, and Fig. 9 C represents the position relation between pit and the laser beam, Fig. 9 D represents to reproduce waveform (it is the output of detecting signal unit 22), Fig. 9 E represents PR (1,1) characteristic, and Fig. 9 F represents PR (1,2,1) characteristic, Fig. 9 G represents PR (1,2,2,1) characteristic.

As shown in Figure 9, according to the wave recording NRZI form (Fig. 9 B) corresponding to record data (Fig. 9 A), form pit (mark) string in advance on CD 1, described record data are the information that will write down.

When reproduction is recorded in information on the CD 1, with the form of the beam spot shown in the oblique line among Fig. 9 C, from the laser diode 11 of pick-up 21, the reproduction laser light beam on the pit string of CD 1.By this operation, can obtain whether to exist according to pit, and the reflection lasering beam of the direction of polarization light in change reflectivity or the beam spot.The laser light reflected bundle is received by the detecting signal unit shown in Fig. 5 22, and the experience signal Processing, thus the information of playback record on CD 1.That is, can obtain and be recorded in the reproducing signal of the information correspondence on the CD 1 according to by by 13 pairs of outputs that obtain from CD 1 laser light reflected Shu Jinhang opto-electronic conversion of the photodetector shown in Fig. 4.

As shown in Fig. 9 D, according to PR (1,1) characteristic, PR (1 respectively, 2,1) characteristic and PR (1,2,2,1) characteristic, 64 pairs of reproducing signals of balanced device (because the cause of the characteristic of recording/reproducing system, (Fig. 9 A) compares with record data, and this reproducing signal is blunt waveform) carry out equilibrium.

PR (1,1) characteristic was wherein at two continuous identification points the range value of two channel clocks reproduction waveform constantly (promptly), the characteristic of impulse response occurred with 1: 1 ratio.

That is, Fig. 9 corresponding to the wave recording of the NRZI form of the first " 010010 " of the record data of Fig. 9 A by following statement 011100.

Be counted as impulse response owing to reproduce waveform for the wave recording of " 1 ", state the linear superposition of following response as and the waveform of Fig. 9 E of obtaining with " 012210 " form to become the quilt equilibrium be the target waveform of PR (1,1) characteristic (type).

0110

00110

000110

PR (1,2,1) characteristic was wherein three continuous identification points (promptly being positioned at the range value of the reproduction waveform of three channel clock timing), the characteristic of impulse response occurred with 1: 2: 1 ratio.

In addition, PR (1,2,2,1) characteristic is wherein four continuous identification points (promptly being positioned at the range value of the reproduction waveform of four channel clock timing), and with 1: 2: 2: the characteristic of impulse response appearred in 1 ratio.

That is, the same with the situation of PR (1,1) characteristic, the balanced target waveform of wanting that obtains by the linear superposition corresponding to the impulse response of wave recording becomes waveform (though not shown, this also is applicable to other PR characteristic) shown in Fig. 9 F and 9G.

Can find out from Fig. 9 E, 9F and 9G, according to PR (1,1) characteristic, the order of PR (1,2,1) characteristic and PR (1,2,2,1) characteristic, the characteristic of the waveform after the equilibrium becomes more and more blunt characteristic gradually.

As mentioned above, in the PRML system,, can suppress the increase of Signal Degrade component in the balanced device 64 by the reproduction waveform that the waveform of the PR characteristic that converts the characteristic that more approaches to reproduce waveform from CD 1 laser light reflected bundle to is obtained is carried out equilibrium.

Equalized waveform from balanced device 64 is decoded by ML demoder 65, and is provided for RLL detuner 66 as binary data.

If balanced device 64 becomes PR (1,2,2 reproducing wave shape equalization, 1) waveform of characteristic, then ML demoder 65 is from satisfying PR (1,2,2,1) all of characteristic are reproduced in the wave sequence, selection has the sequence of least error with respect to the sample sequence of equalized waveform, and when tracking mode changes, estimate and export the record data (binary data, decoded data) in the source of the reproduction wave sequence of selecting as generation.

Figure 10 A～10C is the synoptic diagram of the example of the decoding carried out of explanation ML demoder 65.

In the PRML system, not according to a sample value, but by as prerequisite, carrying out decode procedure according to a series of sample values resulting from the correlativity (waveform interference) of PR characteristic of a series of a plurality of sample values.Therefore, to not having the Signal Degrade component of any correlativity between the sample value, there is advantages of higher stability in the PRML system.

Promptly, by " sample sequence of equalizing signal " and the correlativity " sequences that ML demoder 65 select " between of basis as shown in Figure 10 A, obtain " the selecting the signal level of sequence " shown in Figure 10 B, can obtain the decoded data as shown in Figure 10 C, promptly identical decoded data with the decoded data of Fig. 9 A.

That is, as shown in Figure 10 A～10C, the following balanced signal waveform sequence that obtains afterwards of PR (1,2,2,1) that is given in.

01355311356531...

The following impulse response that provides candidate record data (01010...) (wave recording is 01100...).

012210...

001221...

Subsequently, following acquisition is by the reproduction waveform of the desirable PR characteristic of the linear superposition acquisition of above-mentioned impulse response.

013431...

In addition, the following impulse response that provides another candidate record data (01110...) (wave recording is 01110...).

0122100...

0012210...

0001221...

Subsequently, following acquisition is by the reproduction waveform of the desirable PR characteristic of the linear superposition acquisition of above-mentioned impulse response.

0135531...

Afterwards, calculate cross correlation, and utilize probabilistic method, select to have the sequence of maximum correlation (least error between=sequence) with respect to reproducing equalized waveform with respect to the wave sequence of above-mentioned reproduction waveform.

Attention can increase and amount to the number of candidate's waveform as with tree structure.But when considering the PR characteristic, the number of upstate is limited.At PR (1,2,2,1) under the situation of characteristic, constraint length (waveform disturbs the scope that exerts an influence) is " 4 ", 16 kinds of combinations that waveform disturbs the variation of the record data sequence that causes to produce the 4-digit number value that is made of two kinds of data values " 0 " and " 1 " are so break-even status number mostly is 16 most.If modulation code is limited, then status number might be reduced.

When the supposition state when a certain state exchange becomes NextState, ML demoder 65 is according to input sample value calculating probability.When a plurality of candidate's wave sequence that is transformed into equal state is provided,, determine possible candidate's wave sequence in candidate's wave sequence according to the transition probabilities in past.

For this reason, ML demoder 65 is furnished with the path memory (back utilizes Figure 30～34 explanations) of preserving candidate's wave sequence.Usually, its length is configured to the length of dozens of channel bit.When by path memory, a plurality of candidate's wave sequences are transformed into equal state, select candidate's wave sequence subsequently repeatedly, select most probable wave sequence at last.Though unspecified, ML demoder 65 comprises the branch metric calculation unit, ACS (this is the abbreviation of addition-comparison-selection piece circuit) and path metric storer.The logarithm value of branch metric calculation unit computing mode transition probabilities, the logarithm value of state-transition probability is with when importing sample value, if the supposition state becomes next candidate state from a certain state-transition, actual magnitude that obtains and the difference between the desirable amplitude are represented, the path metric storer is to be kept at the state-transition of every kind of state of executing state number repeatedly, and before the acquisition state, the storer of the branch metric accumulated value in the past of acquisition.Because well-known, most probable sequence is selected by the ML demoder, therefore it is not elaborated here.

Refer again to Fig. 7, signal determines that circuit 25 is used to change between limiter system shown in Fig. 7 and PRML system.

After setting up linear superposition, even the shortest mark/pit has less range value, the PRML system also can reproducing signal.On the contrary, in the level limiter system, because the range value that requires the shortest mark/pit is greater than certain level, with regard to the wave sequence that signal intensity is lowered, this system is unfavorable.In the present invention, signal determines that circuit 25 reproduces the signal that waveform obtains according to handling by PRML system and level limiter system, confirms from preferred condition of CD 1 reproducing signal and characteristic.Therefore, according to CD 1 intrinsic characteristic and the required preferred reproducing condition of reproducing signal, reproduce the information that is recorded on the CD 1.

Drive and Control Circuit 26 can be according to the output of determining circuit 25 from signal, promptly according at least from the signal of one of any output of PRML signal processing circuit 24 and level clipped signal treatment circuit 23, the output switching signal is to be reproduced by PRML signal processing circuit 24 or with the selection signal that is reproduced by level clipped signal treatment circuit 23.

For example, response offers its selection signal from Drive and Control Circuit 26, and the level limit is opened every the switch 59 of signal processing circuit 23, thus select by level clipped signal treatment circuit 23 carry out according to the signal reproduction that reproduces waveform.

In addition, response offers its selection signal from Drive and Control Circuit 26, and the switch 59 of PRML signal processing circuit 24 is opened, thus select by level clipped signal treatment circuit 23 carry out according to the signal reproduction that reproduces waveform.

Drive and Control Circuit 26 is according to address date, and to servo controller 32 output predetermined control orders, described address date is relevant with the data that data that obtain according to the data from host device interface 28 instructions and error correction unit 27 obtain.By this operation, optical pickup apparatus 21 is moved to the precalculated position, and the revolution of spindle motor 33 is configured to the revolution corresponding to the zone of access location.

The following describes by the information record on the top CD of carrying out with reference to the optical pickup apparatus of figure 4 explanation 1 with from the information regeneration of CD 1.

Pass polarization spectroscope (PBS) 14 and quarter wave plate 15 from the laser beam that the laser diode 11 as light source sends, be drawn towards object lens 12.Give the convergence character of laser beam by object lens 12, the laser beam of guiding object lens 12 into converges to the precalculated position of CD 1, promptly converges to the predetermined depth of track or groove.

Attention is the plane of polarization electric field component parallel with the plane of incidence of PBS14 (P polarized light) from the component (this component is drawn towards CD 1) of the laser beam that laser diode 11 sends, be reflected PBS reflection of the electric field component that plane of polarization is vertical with the plane of incidence (S polarized light).

Quarter-wave long wave 15 is by the optical crystal with predetermined birefringence value being cut into the film-shaped device corresponding to the predetermined thickness formation of laser beam wavelength, the linearly polarized photon that sends and pass the P polarized light of PBS14 from laser diode 11 is converted to circular polarized light, and the circular polarization of CD 1 laser light reflected bundle is converted to linearly polarized photon.Promptly, when the polarization direction of light of the laser beam of sending from laser diode 11 is configured to the x direction, and PBS14 is arranged to make the polarized light component of x direction to pass it, and reflection is perpendicular to the y direction polarized light component of x direction, pass PBS14 same as before from the laser beam that laser diode 11 sends, after the direction on its polarized light surface is converted to circular polarized light by quarter wave plate 15, be incident on the object lens 12.On the contrary, make CD 1 reflection and return object lens 12, and the reflection lasering beam that its polarization direction of light is a circular polarized light passes quarter wave plate 15 once more, thereby make reflection lasering beam become linearly polarized photon, the polarization direction of light is pointed to the y direction of principal axis.

Therefore, from CD 1, the reflection lasering beam that returns PBS14 is reflexed to photodetector 13 by PBS14, carries out opto-electronic conversion by photodetector 13, and is used to export the reproduction waveform that is used to obtain reproducing signal.

The following describes when in CD 1, having birefringence the variation of signal intensity.When its polarization direction of light has been converted to circular polarized light by quarter wave plate 15 laser beam is reflected by CD 1, when the value of the phase delay on the y direction of representing with γ to be caused by birefringence, the intensity of laser beam of the return laser light element 11 of reflection lasering beam is for guiding the sin of the intensity of laser beam of CD 1 into from laser diode 11 ²(γ/2) doubly.Therefore, be cos by PBS14 towards the intensity of photodetector 13 laser light reflected bundles ²(γ/2) doubly.That is, if result from birefringent phase delay γ for " 0 ", then the laser light reflected bundle is penetrated fully on photodetector 13, and as phase delay γ greatly the time, the intensity of laser beam of penetrating on photodetector 13 is lowered 1-sin ²(γ/2).Because the laser beam of return laser light element 11 also is the factor that increases the noise of laser beam, therefore suppress the laser beam of return laser light element 11 as much as possible.

More particularly, when the intensity of laser beam that penetrates from laser part 11 is represented with " a ", penetrate from laser part 11, the laser beam Ein that is incident on the PBS14 is represented by the expression formula (1) shown in following.

$\mathrm{Ein}=\left[\begin{array}{c}\mathrm{Ex}\\ \mathrm{Ey}\end{array}\right]=a\left[\begin{array}{c}\cos \mathrm{wt}\\ 0\end{array}\right]...\left(1\right)$

When quarter wave plate 15 is arranged to heeling condition, thereby when laser beam incident thereon has 45 ° position angle, expression formula (2) the expression laser beam Ein shown in below then using.

$\mathrm{Ein}=\left[\begin{array}{cc}\cos 45& \sin 45\\ -\sin 45& \cos 45\end{array}\right]\·\left[\begin{array}{c}\mathrm{Ex}\\ \mathrm{Ey}\end{array}\right]=\frac{a}{\sqrt{2}}\left[\begin{array}{c}\cos \mathrm{wt}\\ -\cos \mathrm{wt}\end{array}\right]...\left(2\right)$

Owing to pass the laser beam Eout of quarter wave plate 15 ₁The phase place of y durection component be delayed pi/2, thereby with expression formula (3) the expression laser beam Eout shown in following ₁

$\mathrm{<figure-callout\; id="1"\; label="Eout"\; filenames="A200410031560.X00531.png,A200410031560.X00591.png"\; state="\{\{state\}\}">Eout</figure-callout>}1=\frac{a}{\sqrt{2}}\left[\begin{array}{c}\cos \mathrm{wt}\\ -\cos (\mathrm{wt}-\frac{\mathrm{\&pi;}}{2})\end{array}\right]...\left(3\right)$

$=\frac{a}{\sqrt{2}}\left[\begin{array}{c}\cos \mathrm{wt}\\ -\sin \mathrm{wt}\end{array}\right]$

When expression (3) on coordinate system x-y, represent laser beam Eout described above with the expression formula (4) shown in following ₁

$\mathrm{<figure-callout\; id="1"\; label="Eout"\; filenames="A200410031560.X00531.png,A200410031560.X00591.png"\; state="\{\{state\}\}">Eout</figure-callout>}1=\left[\begin{array}{c}\mathrm{Ex}\\ \mathrm{Ey}\end{array}\right]=\frac{a}{\sqrt{2}}\left[\begin{array}{c}\cos (\mathrm{wt}-\frac{\mathrm{\&pi;}}{4})\\ \cos (\mathrm{wt}+\frac{\mathrm{\&pi;}}{4})\end{array}\right]...\left(4\right)$

On pit (mark) string, groove or the convex ridge that are being radiated the CD 1 under this state, and from the reflection lasering beam Eref of CD 1 reflection, during along y direction generation phase delay γ, represent reflection lasering beam Eref with the expression formula (5) shown in following.

$\mathrm{Ereg}=\left[\begin{array}{c}\mathrm{Ex}\\ \mathrm{Ey}\end{array}\right]=\frac{a}{\sqrt{2}}\left[\begin{array}{c}\cos (\mathrm{wt}-\frac{\mathrm{\&pi;}}{4})\\ \cos (\mathrm{wt}+\frac{\mathrm{\&pi;}}{4}-\mathrm{\&gamma;})\end{array}\right]...\left(5\right)$

When expression (5) on coordinate system x-y, represent above-mentioned laser beam Eref with the expression formula (6) shown in following.

$\mathrm{Ereg}=\left[\begin{array}{c}\mathrm{Ex}\\ \mathrm{Ey}\end{array}\right]=a\left[\begin{array}{c}\cos (\mathrm{wt}-\frac{\mathrm{\&gamma;}}{2})\cos (\frac{\mathrm{\&pi;}}{4}-\frac{\mathrm{\&gamma;}}{2})\\ -\sin (\mathrm{wt}-\frac{\mathrm{\&gamma;}}{2})\sin (\frac{\mathrm{\&pi;}}{4}-\frac{\mathrm{\&gamma;}}{2})\end{array}\right]...\left(6\right)$

When making reflection lasering beam Eref pass quarter wave plate 15 again, it becomes reflection lasering beam Eout ₂, the phase place of its y durection component is delayed pi/2, represents reflection lasering beam Eout with the expression formula (7) shown in following ₂

$\mathrm{<figure-callout\; id="2"\; label="Eout"\; filenames="A200410031560.X00531.png,A200410031560.X00591.png"\; state="\{\{state\}\}">Eout</figure-callout>}2=a\left[\begin{array}{c}\cos \frac{\mathrm{\&gamma;}}{2}\\ \sin \frac{\mathrm{\&gamma;}}{2}\end{array}\right]\cos (\mathrm{wt}-\frac{\mathrm{\&gamma;}}{2})...\left(7\right)$

Therefore, pass the reflection lasering beam Eref (Eout of quarter wave plate 15 for twice with the expression of the expression formula (8) shown in following ₂) intensity I out.

$\mathrm{Iout}=\left[\begin{array}{c}\mathrm{Ix}\\ \mathrm{Iy}\end{array}\right]=a^2\left[\begin{array}{c}{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="A200410031560.X00531.png,A200410031560.X00591.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2\frac{\mathrm{\&gamma;}}{2}\\ \cos \frac{\mathrm{\&gamma;}}{2}\end{array}\right]...\left(8\right)$

That is, return the laser beam Eout of PBS 14 ₂Pass reflection lasering beam PBS 14, and the intensity I x of the return laser beam of return laser light element 11 is represented by the expression formula (9) shown in following, reflected by PBS 14, and the intensity I y of reflection lasering beam that guides photodetector 13 into is by the expression of the expression formula (10) shown in following.

Ix＝a ²sin ²(Δγ/2)?????????????(9)

Ix＝a ²cos ²(Δγ/2)?????????????(10)

When the influence owing to birefringence, when causing phase delay γ, the intensity that is incident on the reflection lasering beam on the photodetector 13 is for guiding the cos of the intensity of laser beam of CD 1 into from laser diode 11 ²(γ/2) doubly.

Incidentally, in the DVD CD that uses at present, the following upper limit is configured to when use is passed through to measure birefringence for twice, and the value of birefringence is so that suppress the reduction of the intensity of photodetector 13 detected signals.

This upper limit is configured to:

(standard ECMA-267 is 100 nanometers in read-only optical disc p15) (below abbreviate DVD-ROM as) at dvd standard;

(standard ECMA-279 is 100 nanometers in p16) at the DVD-R that can only write down primary information;

(standard ECMA-272 is 60 nanometers in p13) at DVD-RAM that can rewrite information.

In addition, just measure the method for birefringence, standard ECMA-267 the 41st page with 42 pages of explanations " by becoming 7 ° angle with the direction with respect to vertical CD, the laser beam of radiation wavelength 640 ± 15 nanometers is measured birefringence ".

Note by " γ=Δ/λ * 360 °, λ here: optical maser wavelength ", can determine the value of the phase delay γ that the influence by birefringence causes according to birefringence.

Therefore, in the DVD CD, birefringence and the relation between the intensity of laser beam on the photodetector 13 of being incident on are by table 1 expression shown in following.

Table 1

Birefringence (nm)	Signal intensity (%)
		????0	????100.0
????10	????99.8
		????20	????99.1
????30	????97.9
		????40	????96.3
????50	????94.3
		????60	????91.8
????70	????89.0
		????80	????85.8
????90	????82.3
		????100	????78.4

When look-up table 1 and birefringence regular, in DVD-ROM and DVD-R, allow reduction up to 78.4% signal intensity, in DVD-RAM, allow reduction up to 91.8% signal intensity.Because the DVD-RAM CD innately has low reflection coefficient, and rewrite further deterioration signal, therefore require signal intensity greater than DVD-ROM and DVD-R CD, thus the strict specification of determining the DVD-RAM CD.

Incidentally, in the system that signal amplitude (signal intensity) reduces, signal is amplified by amplifier usually.But undoubtedly, simple amplifying signal is without any effect, because noise component is increased simultaneously, C/N (S/N) is than remaining unchanged.

In addition, owing to need exquisiter information, therefore need utilize above-mentioned PRML signal Processing to increase recording capacity as image source.Good, in widely used level clipped signal disposal system, when reducing pit (mark) big or small simply, be subjected to disturbing from the waveform of adjacent pit owing to reproduce waveform, therefore only can not determine data according to a pit.

But, even in the PRML signal processing system, still exist waveform to disturb, utilize and from the sequence of considering the waveform front-end and back-end, select the ML demoder of reliable sequence, can detect with higher error rate and reproduce waveform.

It should be noted, in the level amplitude-limiting equalizer of routine, according to position with respect to the intersection point that reproduces threshold value that waveform is provided with and equalized waveform, determine that binary data is (by carrying out equilibrium treatment, intersection point is placed window center, detect intersection point), the binary data that obtains by the detection intersection point is carried out NRZI (oppositely non-return-to-zero) conversion, obtain decoded data (data that are recorded on the CD are decoded).

Incidentally, because the influence of noise etc., the intersection point of equalized waveform and threshold value always is not positioned at the center of window.Thereby when utilizing window width to make its standardization, the standard deviation of intersection point place data is called as shake, and shake is used as the assessment reference of CD and disc drives.

Check the optical head (optical pickup apparatus) of the dvd standard CD design be utilized as present use below, from a kind of situation with the optical disc replay information of the higher density recording of information of the DVD that uses than the present invention.

Higher track density makes reproducing signal comprise the signal degradation component (being called crosstalk components) of bigger quantity.On the contrary, higher line density causes more blunt reproduction waveform.

Because the high fdrequency component of utilizing balanced device to amplify reproducing signal as mentioned above,, must further amplify high fdrequency component when input when to reproduce waveform be more blunt reproduction waveform.Thereby above-mentioned signal corruption component is obviously also amplified by balanced device.

Incidentally, as mentioned above, owing to as above utilize the influence of the birefringence of table 1 explanation, in DVD-ROM, signal intensity is lowered to 78.4%, and in DVD-RAM, signal intensity is lowered to 91.8%.

When the influence of birefringence was applied to the recording/reproducing system of CD and the laser beam of using 405 nano wave lengths, even allow the same big signal intensity with the DVD CD to reduce, the value of the birefringence of permission still is greatly reduced, and was as shown in table 2.

Table 2

Birefringence (nm)	Signal intensity (%)
		????0	????100.0
????10	????99.4
		????20	????97.6
????30	????94.7
		????40	????90.7
????50	????85.7
		????60	????79.9
????70	????73.3
		????80	????66.2
????85	????62.5
		????90	????58.7
????100	????51.0

When as shown in table 2, when using the birefringent standard value (100 nanometer) of DVD-ROM and DVD-R, in DVD-ROM and DVD-R, signal intensity is halved, and is among the DVD-RAM of 60 nanometers in birefringent standard, and signal intensity is lowered to about 80%.Therefore, when record with during information reproduction, mistake appears being easy to produce, and can not accurate recording and the problem of information reproduction.

Especially, in the RLL modulation of in the recording/reproducing system of CD and the laser beam of using 405 nano wave lengths, checking, because the shortest mark is 2T signal (number that wherein allows to be present in " 0 " between the numeral " 1 " of front-end and back-end of expression pit (mark) string is 1 register system), so the minimum value of signal intensity is further reduced.

Consider the problems referred to above, the present invention will check following two kinds of systems.

First is when tracer signal on the CD of dvd standard, and during from the optical disc replay information of dvd standard, uses the waveform limiter system utilized the at present situation as signal processing system.In this case, can foundation and the CD of dvd standard in the same principle used check birefringent ultimate value.

In the system of the laser beam of determining use 405 nano wave lengths according to table 2, (described numerical value satisfies the allowed band (signal intensity of DVD-ROM and DVD-R: 78.4% or bigger of the signal intensity of the dvd standard CD of determining according to table 1 during the numerical value of birefringence, the signal intensity of DVD-RAM: 91.8% or bigger)) time, in ROM (read-only) CD and R (can only write down once) CD, the numerical value of birefringence is 60 nanometers or littler, in RAM (can write down and can wipe) CD (below be called recording/reproducing optical disk), the numerical value of birefringence is 40 nanometers or littler.

Promptly, in ROM (read-only) CD and R (can only write down once) CD, the value of birefringence is 60 nanometers or littler, in RAM (recoding/reproduction) CD, the numerical value of birefringence is 40 nanometers or more hour, even utilize the compact disk equipment of the laser beam of using 405 nano wave lengths, also can stably write down and information reproduction.

Second is S/N (signal to noise ratio (S/N ratio)) when reproducing signal when being lowered, and uses the situation of effective PRML system as the reproducing signal disposal system.

In the PRML system, because the front utilizes the ML of Fig. 6,7 and 9 explanations to determine to compare the effect of circuit with regard to S/N, the level of reproducing signal can be increased about 2dB.This means and utilize the signal amplitude inspection at that time, the situation that ML is not determined is compared, and utilizes 80% signal intensity can obtain the reproducing signal of par.

That is, when signal amplitude be in the waveform limiter system wave-shape amplitude 80% the time, use the PRML system to allow stably to write down and information reproduction.When using the PRML system,, then can stably write down and information reproduction if obtain the signal amplitude of signal amplitude 90% in the waveform limiter system.

Therefore, when using the PRML system, for the tolerance band of signal intensity in the dvd standard CD that can determine according to table 1 (be 78.4 or bigger in DVD-ROM and DVD-R, be 91.8% or bigger in DVD-RAM) 80% signal intensity (in ROM and R CD, be 62.7% or bigger, be 73.4% or bigger in the RAM CD), be the lower limit of the required signal intensity of reproducing signal.

According to top described, when the birefringence numerical value that utilizes table 2 to determine can to obtain as the signal intensity of the lower limit of dvd standard CD, in ROM and R CD, this numerical value is 85 nanometers or littler, and in the R CD, this numerical value is 70 nanometers or littler.

Similarly, the signal intensity of the signal intensity 90% in can obtaining to the dvd standard CD in the signal intensity tolerance band is (in DVD-ROM and DVD-R, be 70.6% or bigger, be 82.6 or bigger in DVD-RAM) birefringence value, during as the standard of the birefringence value that can guarantee this signal intensity better, in ROM and R CD, this value is 75 nanometers or littler, is 55 nanometers or littler in the RAM CD.

As mentioned above, when in signal Processing, using the PRML system, even owing to reach aforesaid birefringent influence in the compact disk equipment in the CD, signal intensity is lowered, still can reliable recording and information reproduction, described CD can be by the laser beam of 405 nano wave lengths record and information reproduction, described compact disk equipment can be on CD recorded information, and from optical disc replay information.

Utilize Fig. 3 below, illustrate in greater detail above utilizing the CD that the process with reference to Figure 1A～1E and Fig. 2 A～2C explanation forms.

By formation metal film or dye film on the molded matrix 1a that forms in the mold process of Fig. 1 (is reflectance coating in read-only optical disc, in only writing down CD is organic recording layer, be phase change recording film in CD-RW) 2, utilize ultraviolet curable resin (not specifying) subsequently, 1b is adhered on the molded matrix 1a another molded matrix (or pseudo-matrix), forms CD 1.On the laser beam incident face of molded matrix 1a, form hard coat (not specifying), exempt to be scratched with stained with the protection CD.When on read-only (ROM) CD, applying recording layer 2 (it is metal film or dye film), the metal by sputter or vacuum moulding machine such as Al, Ag, the recording layer 2 of about 100 nanometers of formation thickness.When recording layer 2 is to be used in when writing down an organic recording layer in the CD only, by spin coating, coat the dye materials of thickness 100 nanometers, this dye materials can absorb 405 nanometer laser bundles reliably.When record 2 when being the phase change recording film that is used in the recording/reproducing optical disk, form the film of predetermined metal or alloy by sputter etc.

Under the state that is placed on the spinner (not specifying), go up coating ultraviolet curable resin 3 at least one resin molded thin slice ( matrix 1a or 1b).Subsequently, after relative matrix is placed on the resin molded thin slice, resin molded thin slice is placed vacuum, so that remove the bubble that is included in the ultraviolet curable resin 3.Subsequently, after with predetermined pressure extruding ultraviolet curable resin 3, with ultraviolet irradiation and curing ultraviolet-curing resin 3.

The resin of the about 400cps of viscosity can be used as ultraviolet curable resin, uses Dainippon Ink and Chemicals in the present embodiment, the resin SD649 that Incorporated produces.

When the drippage ultraviolet curable resin, the revolution of spinner is configured to 60RPM, and when splashing down resin, the revolution of spinner is configured to 8000RPM, is about 25 microns resin bed thereby obtain thickness.

On the contrary, utilize for example Toshiba Machine Co., the molded thin slice of DVD injection (mo(u)lding) machine (IS40HD) injection molding resin ( matrix 1a or 1b or pseudo-matrix) that Ltd. produces.For example the polycarbonate resin (AD-5503) of Teijin Chemicals Ltd. production can be used as matrix material.

As mentioned above, compare with the size of dvd standard CD, less by the size of pit (mark) that the laser beam of 405 nano wave lengths can information reproduction, similarly by laser beam with above-mentioned wavelength, in can CD of record only of recorded information, and in recording/reproducing optical disk, track space is narrower.

Therefore, when molded matrix, be difficult to shift the pattern that is formed on the pressing mold reliably, and suppress birefringent value.Especially, in the Write-once optical disc of coated dye layer,, therefore require greatly to improve transfer characteristics thereon because groove is full of dyestuff.

Though the characteristic of molded matrix depends on the expression injection pressure, the mould clamping pressure, stroke (stroke) time, the selection of time of clamping mould, many parameters such as metal mold temperature, however in the present embodiment, mainly note the metal mold temperature.

Glass transformation temperature as the polycarbonate resin of matrix material is about 150 °, and the rising of metal mold temperature is restricted.But, exist by rising metal mold temperature, suppress the tendency of birefringent value.So, in the present embodiment,, form multiple CD, and assess described multiple CD with the method that describes below by changing the metal mold temperature, determine top condition according to assessment result.

Characteristic as the CD of sample is as described below.

After utilizing the substrate of base plate exposure machine generation as ROM (read-only) CD of the Kr laser beam of using 351 nano wave lengths, it is 0.205 micron that use records the shortest mark lengths thereon by cutting, track space is 0.40 micron, and pit depth is the plating Ni pressing mold of the Data transmission of 70 nanometers.

At this moment, prepared five kinds of molded matrix, i.e. sample A, B, C, D, E, every kind of molded matrix has different birefringences.

The internal diameter of the every kind of matrix that forms is 15 millimeters, and external diameter is 60 millimeters, and thickness is 0.60 millimeter.Utilize sputter equipment, form the Al film of thickness 100 nanometers on molded matrix, by ultraviolet hard resin, this matrix is adhered on another molded matrix.

Birefringence at these samples of position measurement of 40 millimeters of radiuses.

Utilize Admon Science, the birefringence measurement device that Inc. produces, and adopt can the output blue laser beam (wavelength: laser diode 400 nanometers) is measured birefringence as light source.The birefringence measurement device can be measured the phase change of the laser beam on the record surface that is reflected in CD exactly.

In order to assess birefringence, according to standard ECMA-267, the rule of p41-42, with tilt 7 ° angle perpendicular to the direction of CD, make laser beam incident on CD.

By making laser beam, can utilize once by measuring birefringence by single molded matrix (matrix).But when passing through the CD of bonding two matrixes manufacturing, owing to the influence of stress in the matrix and distortion, the birefringent value of measuring in single matrix is changed.Thereby preferably utilize from the laser beam of the CD reflection of forming by the matrix of actual adhesion, pass through to measure birefringence by twice.

The numerical aperture NA of the object lens of optical pickup apparatus is configured to 0.65, utilizes the characteristics of signals of the laser beam assessment of wavelength 405 nanometers from the laser beam of CD reflection.In addition, for the assessing signal characteristic, as the distinctive information processing of applicant, the assessment error rate.Though use the RLL modulation as the data-modulated system among the present invention, but utilize another modulating system obviously also can obtain identical effect.

The rotated sample CD, thus pit (mark) string moved with the linear velocity of 6.6 meter per seconds, and the readout power of laser beam is configured to 0.5 milliwatt, by the readout power of laser beam is arranged to 0.5 milliwatt, obtains reflection lasering beam from precut data.

The level that utilizes the RF signal of measuring its high reflectance one side is as Rtop, and the signal processing circuit 25 of utilizing earlier in respect of figures 6 to illustrate is determined the method for the error rate of decoded datas, measurement birefringence.At this moment, by use by signal determine circuit 25 arbitrarily the level limiter system and the PRML systems of conversion measure, determine error rate.

According to the reflection lasering beam that obtains by the rotated sample CD, definite birefringent value is used as CD birefringent mean value in one week.

Table 3 has been represented the laser beam that reflexes to signal evaluation means from above-mentioned sample disc A～E by catching, the assessment result of acquisition.In the table 3, the value that Rtop represents to utilize sample A (birefringence is generally " 0 ") is carried out standardized numerical value as benchmark.In addition, with regard to error rate, threshold value that can the stable reproduction signal is configured to 1 * 10 ^-4, the error rate that is equal to or less than threshold value is represented with zero, surpasses the error rate usefulness * expression of threshold value.

Table 3

	Birefringence (nm)	Rtop (standardization)	The level amplitude limit	????PRML
					Sample A	??-3	1.00	????○	????○
					Sample B	??-35	0.94	????○	????○
					Sample C	??-60	0.78	????○	????○
					Sample D	??-81	0.61	????×	????○
					Sample E	??-105	0.45	????×	????×

Can find out that from table 3 increase of spatial map of birefringence magnitude has reduced the value of Rtop.But, in the level limiter system, in sample A～C, allow in the error rate scope of proper range that reproducing signal in the PRML system, in sample A～D, is allowed in the error rate of proper range reproducing signal.Reduce even can find signal intensity,, still increased tolerance limit by adopting the PRML system.

But the recording/reproducing optical disk of table 4 and rewrite information is relevant.Preparation is similar to five kinds of samples that aforesaid ROM changes its injecting condition, and table 4 has been represented the assessment result about the birefringence influence of these samples.Substrate and the similar substrate of pressing mold and the pressing mold of preparation and ROM CD, groove (convex ridge) spacing is configured to 0.68 micron, and data are recorded in (track space is configured to 34 microns) in groove and the convex ridge.In addition, groove is made up of the continuous helical groove of guiding its external diameter from the internal diameter of CD into.

Figure 11 has represented shown in the table 4 example of the multilayer recording film that five kinds of sample disc are total.

As shown in Figure 11, RAM (recoding/reproduction) CD comprises from, the first dielectric layer (ZNSSiO that forms of molded matrix 1a (or 1b) order for example ₂, i.e. diaphragm) and 3, the second dielectric layer (SiO ₂) 4, the three dielectric layer (ZNSSiO ₂, i.e. diaphragm) and 5, recording layer (GeSbTeBi, i.e. multilayer film) 2, the four dielectric layer (ZNSSiO ₂Film, i.e. heat-sink shell=protective seam) 6, reflection horizon (AgNdCu) 7, hard coat (ultraviolet curable resin) 8 etc.Form first dielectric layer, 3～reflection horizon 7 by sputter.

First dielectric layer, 3 thickness are 30 nanometers, and second dielectric layer, 4 thickness are 60 nanometers, and the 3rd medium thickness is 35 nanometers, and recording layer 2 thickness are 15 nanometers, and the 4th medium thickness is 30 nanometers, and reflector thickness is 100 nanometers.

As the evaluation condition of RAM CD, the assessment birefringence is to record data at first, the influence of the reflection lasering beam that obtains when reproducing the data of record subsequently.Record data are random data of experience RLL modulation.

As shown in Figure 12, the modulated laser waveform that is used to write down is used to record data.In Figure 12, Pw represents Writing power, and Pe represents erase power, and Pr represents reproducing power.In addition, by optimizing each power, can overwriting data.As, each power is configured to the Pw=5.2 milliwatt, Pe=2.4 milliwatt, Pr=0.5 milliwatt.In addition, linear velocity is configured to 5.6 meter per seconds, and in the recording process, channel frequence is configured to 64.8MHz.

Under these conditions, around convex ridge recorded information in 5 tracks altogether, reproduce the data that are recorded in the central convex ridge.That is, the leakage of the data of the adjacent orbit that resulting from crosstalks produces, by when the record data in adjacent orbit, the influence of the laser beam of irradiation and the cross erasing that causes etc. are also reproduced.

Table 4

	Birefringence (nm)	Rtop (standardization)	The level amplitude limit	????PRML
					Sample A	-2	1.00	????○	????○
					Sample B	-22	0.98	????○	????○
					Sample C	-38	0.92	????○	????○
					Sample D	-65	0.75	????×	????○
					Sample E	-88	0.60	????×	????×

In the table 4, the value that Rtop represents to utilize sample A (birefringence is generally " 0 ") is carried out the numerical value that standardization obtains as benchmark.In addition, with regard to error rate, threshold value that can the stable reproduction signal is configured to 1 * 10 ^-4, the error rate that is equal to or less than threshold value is represented with zero, surpasses the error rate usefulness * expression of threshold value.The system of earlier in respect of figures 6 explanations is used as signal processing circuit.

Can find out from table 4, though the increase of (sample) spatial map of birefringence magnitude has reduced Rtop,, in the level limiter system, in sample A～C, can be in the error rate of proper range reproducing signal, in the PRML system, in sample A～D, can be in the error rate of proper range reproducing signal.In addition, by adopting the PRML system,, still can increase tolerance limit with respect to the reduction of signal intensity.

Though do not have expression about writing down the detailed evaluation result of a CD only, but, form the substrate and the pressing mold of the depth of groove of the track space that all has 0.40 micron and 100 nanometers by being similar to the similar manufacture process of aforementioned recording/reproducing optical disk.Subsequently, preparation is respectively by two samples that matrix is formed with dye film formed thereon, and ROM and RAM CD in each sample disc, are assessed the signal intensity of reflection lasering beam similarly.

Because the degree of depth of the groove that forms consider that they are full of dye film, so mold pressing parameter is changed the mold pressing parameter that can shift the pattern that cuts exactly on pressing mold greater than the degree of depth of ROM and RAM CD further groove.

In this case, though increased the amount of crimp that in single matrix, produces, by optimizing bond condition, crimpness falls in the critical field.

The spinner coating thickness is about the cyanine dye of 200 nanometers as dye film, forms the Ag film of about 100 nanometers of thickness as reflectance coating by sputter.Because the birefringent value of sample greater than the birefringent value of RAM CD, can obtain to have and above utilize the sample that birefringence distributes like the ROM disc of table 3 explanation.

On-line velocity is configured to 6.6 meter per seconds, channel frequence is configured under the evaluation condition of 64.8 MHz in the record, be similar to RAM CD assessment sample, its birefringent value is about in 60 nanometers or the littler sample in the level limiter system, and in the PRML system, its birefringent value is about in 85 nanometers or the littler sample, can be under suitable error rate reproducing signal.

Incidentally, in laser beam by 405 nano wave lengths, can be from its information reproduction, and laser beam by identical wavelength, thereon in the CD of recorded information, and information is being recorded on the CD, and from the compact disk equipment of optical disc replay information, intrinsic information be recorded in advance CD originally on one's body.In addition, be recorded in information on the CD by reproduction, compact disk equipment can be optimized record condition and reproducing condition.

Following order declare record is at information on the CD and the example that can reproduce the feature of the compact disk equipment that is recorded in the information on the CD.

CD 1 has 1) ROM (read-only) CD, 2) can only write down write-once type (R) CD and 3 of primary information) the total data ordering structure of RAM (the recoding/reproduction type gets final product rewriting type) CD.That is, but present embodiment mainly emphasizes to guarantee to be divided into the compatibility between read-only type, write-once type and rewriting type information recording carrier (CD 1), shown in Figure 13 following some, above-mentioned various information recording medium has common structure:

(a) information recording carrier has Lead-In Area, data field and the data leading-out zone of common arrangement;

(b) Lead-In Area is divided into system's Lead-In Area and the data importing district that is positioned at the two ends, bonding pad usually;

(c) but read-only type, write-once type and rewriting type all allow single layer structure (single reflection layer or single recording layer) and double-decker (have two reflection layers or two recording layers, thereby can from a surface-rendering information); With

(d) information recording carrier has identical thickness, internal diameter and external diameter.

As shown in Figure 14, formation system Lead-In Area in two read-only layers (reverse (opposite) orbital paths) only.Note comprising Lead-In Area the optical disc data district arrangement as shown in Figure 15.

In superincumbent (a)～(d), (a) and (d) item also is applicable to known dvd standard CD.In the present embodiment, will specify the feature of (b) item.

According to the pattern of CD, the block of information in the CD is divided into five parts.That is, CD has system's Lead-In Area, bonding pad, data importing district, data field and data leading-out zone.The block of information has the track of being made up of concavo-convex pit string.

Track in system's Lead-In Area is a week 360 ° a continuous helical track.The track of data importing district, data field and data leading-out zone all is a week 360 ° a continuous helical track.The center of track is consistent with the center of pit.

In the DVD CD that uses at present, but read-only type, write-once type and rewriting type information recording carrier also all are provided with Lead-In Area.In addition, be called as concavo-convex (embossed) but Lead-In Area and with careful recessed-pit district that convex form forms is present in the rewriting type information recording carrier (DVD-RAM CD and DVD-RW CD) and Write once information recording medium (DVD-R CD) in the DVD CD of present use.

Among but rewriting type and Write once information recording medium were arbitrary, the degree of depth in pit district was consistent with the degree of depth of forward recess (pregroove) in the data field.

In the DVD-ROM CD that uses at present, promptly in the read-only information recording carrier in the DVD CD that uses at present, the optimum depth of pit is λ/(4n), and λ represents the wavelength that uses here, and n represents the reflection coefficient of matrix.

In the DVD-ROM CD that uses at present, but promptly in the rewriting type information recording carrier in the DVD CD that uses at present, reduce to minimum condition as making from crosstalk (with respect to the leakage rate of reproducing signal) of the record mark of adjacent orbit in the data field, the optimum depth of pre-fluting is λ/(5n)～λ/(6n).

Therefore, in the DVD-RAM that uses at present, according to above-mentioned optimum depth, the pit depth in the concavo-convex Lead-In Area is configured to λ/(5n)～λ/(6n).

From the degree of depth is the pit of λ/(4n) or λ/(5n)～λ/(6n), can obtain the enough big reproducing signal of value (because the degree of depth of pit is enough big).

Compare with above-mentioned, in the DVD-R CD that uses at present, because the degree of depth of data field further groove is very shallow, the pit that can not have same depth from concavo-convex Lead-In Area obtains the bigger reproducing signal of value, thus produce can not the stable reproduction signal problem.

In order to address the above problem, but being characterised in that to read-only type, write-once type and rewriting type information recording carrier, present embodiment provides system's Lead-In Area, and make track space in system's Lead-In Area and the shortest pit spacing be far longer than track space and the shortest pit spacing (the shortest mark spacing) in data importing district and the data field, so that in the compatibility that guarantees form, guarantee stable reproduction signal from the Lead-In Area of Write once information recording medium.

In the DVD CD that uses at present, utilize the level limiter system to detect reproducing signal (after by binarization, simulating signal is reproduced in output).

In the DVD CD that uses at present, with careful recessed-the shortest pit spacing of the pit that convex form forms, perhaps the cutoff frequency of the characteristic of the OTF (optical transfer function) of the object lens (Fig. 4) that use in the shortest mark spacing of the record mark that is formed by the optical change of the characteristic of recording film and the reproduction optical head is approaching.So, be greatly diminished from the amplitude of the reproducing signal of the shortest pit spacing and the shortest mark spacing.

In addition, when the shortest pit spacing and the shortest mark spacing are reduced, can not utilize the level limiter system to detect reproducing signal.In addition, cause for above-mentioned reasons, the shortest pit spacing of the Write once information recording medium that uses (the DVD-R CD that uses at present) is reduced at present, and generation can not obtain the problem of stable reproducing signal from Lead-In Area.

Present embodiment adopts following measure to overcome conflicting problem.

(α) inside of Lead-In Area is divided into system's Lead-In Area and data importing district, and the track space of the shortest pit spacing in system's Lead-In Area and data importing district all is changed.

(β) in system's Lead-In Area, increase track space and the shortest pit spacing greatly, thereby with respect to amplitude from the reproducing signal of the longest pit spacing, slippage from the amplitude of the reproducing signal of the shortest pit spacing is reduced, thereby, can reproduce signal from system's Lead-In Area in the more shallow Write once information recording medium of pit depth by reproducing signal simply from the shortest pit spacing.

(γ) reduce the shortest pit spacing and the shortest mark spacing, to improve the recording density of data importing district, data field and data leading-out zone, so that improve the memory capacity of information recording carrier itself.

At this moment, replacement is used at present, wherein is difficult to detect the existing level limiter system of reproducing signal (binarization of simulating signal), adopts the PRML system.

(δ) employing is adapted to pass through and reduces the shortest pit spacing and the shortest mark spacing, improves the modulating system of recording density.

Promptly, though in the dvd system that uses at present, wherein be that 0 lowest numeric (according to the numerical value of the d of the restrictive condition of (d and k) after the modulation) is configured to d=2 continuously, be used in combination four kinds of designs after modulating, replace d=2, state the modulating rule that d=1 is adopted in four kinds of designs.This can be realized by the PRML signal processing circuit of earlier in respect of figures 6 explanations.

Attention can make track space and the shortest pit spacing become big in system's Lead-In Area.For this reason, in system's Lead-In Area, utilize the level limiter system of the level clipped signal treatment circuit of the signal processing circuit of using earlier in respect of figures 6 explanations, make the reproducing signal binarization.

In order to illustrate in greater detail, as shown in Figure 15, the mechanical dimension of the information recording carrier of present embodiment is consistent with the mechanical dimension of dvd standard CD, but and and recording medium be that any one is irrelevant in read-only type, write-once type and the rewriting type optical disk.

Therefore, there is risk as described below:

(a) user's possible errors ground is the information recording carrier of present embodiment pack into existing DVD player and existing DVD logging machine;

(b) user's possible errors ground is dvd standard CD pack into the information reproduction device or the information recording/reproduction device of present embodiment.

In order to overcome the problems referred to above, the track space in system's Lead-In Area of the information recording carrier of present embodiment and the shortest concavo-convex pit spacing of concavo-convex pit are configured to the approaching numerical value of size with the Lead-In Area concave convex-concave of dvd standard CD hole, even thereby take place (a) and (b) in the phenomenon of description, in equipment, also can distinguish new medium and old medium, thereby allow to take counter-measure according to the type of medium.

But in the read-only DVD-ROM and rewriting type DVD-RAM CD that use at present, in the Lead-In Area of inner circumferential portion, form the concave-convex pit.But, in the information regeneration and information recording/reproduction device that use at present, utilize the level limiter system, from the concavo-convex pit detection signal of Lead-In Area.In the information regeneration and information recording/reproduction device of present embodiment, the level clipped signal treatment circuit 23 shown in Fig. 7 is used to system's Lead-In Area.

According to present embodiment, but also can be used to be present in the concavo-convex pit in the Lead-In Area of inner circumferential portion of the read-only DVD-ROM CD of present use and rewriting type DVD-RAM CD as same detection circuit with reference to figure 7 explanation, by simplifying its structure, this can reduce the cost of information regeneration and information recording/reproduction device.Even experiment shows that track space and the shortest pit length change the level clipped signal treatment circuit 23 shown in ± 30% Fig. 7 and still can stably detect clipping lever.

The level clipped signal treatment circuit that the slight improvement that is applied to reproduce the existing information reproducer of the information reproduction in the data field of information recording carrier of present embodiment can be utilized existing equipment to be placed in one reproduces the information in system's Lead-In Area of information recording carrier of present embodiment.Thereby the faulty operation shown in even the user carries out above-mentioned (a), the information in also can the playback system Lead-In Area is distinguished this medium, and is notified the user with it.

In addition, the PRML signal processing circuit shown in the most handy Figure 29 is reproduced the signal in data importing district, data field and the data leading-out zone.Attention is except being represented in more detail, and the PRML signal processing circuit shown in Figure 29 is identical with the PRML signal processing circuit of earlier in respect of figures 7 explanations.

When the density that increases record pit or record mark, so that when increasing the capacity of information recording carrier, because the OTF characteristic of top described object lens, can not obtain the amplitude of reproducing signal in the most intensive pit spacing and the most intensive record mark spacing, thereby conventional level limiter system can not stably be carried out signal reproduction and handled.But in the present embodiment,,, can increase the capacity of information recording carrier by increasing the density of record pit and record mark by in signal reproduction is handled, adopting the PRML system.

As described in reference to Figure 13, in the data importing district of read-only information recording carrier, form the identifying code district, in the reproducing circuit in Figure 29 (specifically, for the setting of respective taps coefficient value in the pre-equalizer 123, and in AGC124) adjustment of use automatic circuit.That is, when reproducing identifying code in advance, carry out the automatic circuit adjustment, so that stably reproduce the information be recorded on the data field and detection signal stably.

Therefore,, make the track space in the identifying code consistent with the numerical value in the data field, can improve the automatic adjustment precision of reproducing circuit with the shortest pit spacing by identifying code being placed the data importing district.

Figure 26 and 28 the expression connecting bands (bonding pad) be placed in the CD-R, promptly write-once type (R) but and data importing district in rewriting type (RAM) information recording carrier and the example between system's Lead-In Area.

In the recordable type information recording carrier of present embodiment, but connecting band be placed between the system's Lead-In Area and data importing district by concavo-convex pit record by write-once or regenerative recording label record, thereby system's Lead-In Area is arranged to away from the data importing district.The recordable type information recording carrier of present embodiment has can only be from two recording layers of one side record and information reproduction.

When from one of recording layer information reproduction, another recording layer laser light reflected bundle enters main laser bundle detecting device, thereby produces the phenomenon that is called layer-to-layer signal transfer, and playback signal characteristic is owing to worsening of crosstalking.

Especially, according to being directive system Lead-In Area or directive data importing district by another recording layer laser light reflected bundle, the quantity of laser light reflected bundle differs widely.

Therefore, along recording layer, when following the tracks of once the recording layer from its information reproduction, when because the difference of relative departure centric quantity between two recording layers, when one of two recording layers laser light reflected bundle alternately entered system's Lead-In Area and data importing district, the influence of layer-to-layer signal transfer was increased.In order to overcome this problem, but present embodiment places connecting band between the system's Lead-In Area and the data importing district by write-once or regenerative recording label record that is write down by concavo-convex pit, thereby make system's Lead-In Area away from the data importing district, thereby reduced the influence of layer-to-layer signal transfer, thereby can stably obtain reproducing signal.

In the structure of the read-only information recording carrier shown in Figure 13 as mentioned above, in system's Lead-In Area, arrange initial strip and control data band, between them, insert buffer strip.The sector number of having represented to be positioned at each regional reference position on the right hurdle of Figure 13.

In the system's Lead-In Area shown in Figure 13, initial strip comprises concavo-convex data field.

The master data that is recorded as the Frame of the recorded data zone in the initial strip is configured to " 00h ".Buffer strip comprises 32ECC piece (1024 sector).

The master data that is recorded in as the Frame in the buffer strip of physical sector is configured to " 00h ".

Control data zone comprises concavo-convex data field.This data field comprises concavo-convex (emboss) control data.The bonding pad is used to connected system Lead-In Area and data importing district.

Distance between the center line of the sector " 02 6AFFh " that system's Lead-In Area stops and the center line of the sector " 02 6C00h " that the data importing district begins is configured to 1.4 microns～20.0 microns.

Owing to do not distribute any physical sector number, so the bonding pad does not comprise physical sector number to the bonding pad.Except that the identifying code band, all positions in data importing district are retained.The identifying code band comprises concavo-convex data segment.This data field comprises concavo-convex data code.

Identifying code is made up of the ECC piece that starts from sector number 1965576 (" 02 FFE0h ") (32 sectors).

According to the distribution of master data, the respective sectors of definition master data as described below (2048 byte).

Produce wherein 2048 byte sector of the master data D0～D2047 of repeating data symbol " 164 ".

By hybridization (scramble) data being added in the master data of sector the identifying code of 32 sectors of generation as described below.

Sector 0～15

The hybridization data of initial prevalue " 0Eh " are added in the master data of sector.But the D0～D331 to sector 0 shelters (mask) hybridization data, and does not dose the hybridization data.

Sector 16～31

The hybridization data of initial prevalue " 0Eh " are added in the master data of sector.

The purpose of identifying code is the specific pit pattern that forms 1ECC block length (32 sectors) on CD.Therefore, except that ID, EDC, PI and PO, with data symbol " 164 " (=0A4h) fill the data of record frame before the modulation.

Below, the method that is produced master data by the identifying code of 32 sectors is described.

Because carrying out twice hybridization means there is not hybridization, therefore after mixing, can produce specific data pattern simply.Master data byte (before by hybridization) with the data byte padding data frame of the AD HOC that adds the hybridization value.When normal process these in advance during the data byte of hybridization, recorded data zone comprises all bytes of representing specific data pattern.

D0～the D159 of first sector of ECC piece comprises the continuous data that has DSV before not by hybridization to prevent the uncontrollable big DSV that some PO is capable in this piece (mix unless shelter in advance, otherwise big DSV occurred before modulation).

Figure 14 has represented to have the method for data structure in the double-deck read-only information recording carrier and allocated sector numbering.

Each corresponding data segment comprises 32 physical sectors.The physical sector number of single-layer optical disc or each layer of ptp mode double-layer CD increases in system's Lead-In Area continuously, and in corresponding each layer, and the terminal point from the starting point in data importing district to the data leading-out zone increases continuously.

On OTP pattern double-layer CD, in system's Lead-In Area, layer 0 physical sector number increases continuously, and in corresponding each layer, the terminal point from the starting point in data importing district to zone line increases continuously.

But, the physical sector number of layer 1 has the numerical value that obtains by the physical sector number of inversion layer 0, terminal point (outside) increase continuously from the starting point (outside) in middle zone to the data leading-out zone, the inside from the outside of system's leading-out zone to system's leading-out zone increases continuously.First physical sector number of the data field of layer 1 has the numerical value that obtains by the final physical sector number of the data field of inversion layer 0.Calculating bit reversal numeral, thus place value is configured to 0, and vice versa.

On the double-layer CD of parallel track path PTP, the physical sector with corresponding each layer of common sector numbering is similar to identical to the distance of cd centre.

On the double-layer CD of reverse orbital path OTP, the physical sector of corresponding each layer with bit reversal sector number is approximate identical to the distance of cd centre.

The physical sector number of computing system Lead-In Area, the sector number that consequently is positioned at the sector of system's Lead-In Area afterbody is configured to 158463 " 02 6AFFh ".

Calculate the physical sector number except that the physical sector number of system's Lead-In Area, the sector number that consequently is positioned at the sector of data importing district data field starting point afterwards is configured to 196608 " 030000h ".

As previously mentioned, system's Lead-In Area only is provided with read-only bilayer (reverse orbital path).

The whole master data that records as the Frame of the zone line of physical sector is configured to " 00h ".

The whole master data that records as the Frame of the data leading-out zone of physical sector is configured to " 00h ".

The whole master data that records as the Frame of system's leading-out zone of physical sector is configured to " 00h ".

Data message before " 00h " described above expression modulation.The channel bit pattern of the modulating rule modulation that therefore, will illustrate according to the back is recorded on the information recording carrier.Thereby, in data leading-out zone and system's leading-out zone, spread all over pit string.

Figure 16 has represented the comparison sheet of the packing density in each zone of read-only information recording carrier of present embodiment.

In the present embodiment, because at read-only information recording/regenerating medium (ROM medium) as the information recording/regenerating medium, Write once information recording/reproducing medium (R medium), but adopt identical data structure in the rewriting type information recording/regenerating medium (RAM medium), even therefore in different recording mediums, also can use identical system platform, its favourable part is to be easy to produce finished article, can also improve reliability of products in addition.

Though can obtain above-mentioned advantage by common platform, but provide unnecessary function to having information recording/regenerating medium of different nature, consider the character of the information recording carrier that will deal carefully with, effective application can be proposed thus.

As an example of using, a kind of method of using the zone of being come by the data structure of Lead-In Area is proposed, as a kind of efficient application new method of considering the character of information recording/regenerating medium.

Lead-In Area such as R and RAM medium in the recording medium comprises a read apparatus Lead-In Area of being made up of concavo-convex pit and the data importing district that writes down and reproduce the data that are used for disc drives test, rom test and defect management.But in read-only ROM medium, the function in the data importing district that uses in the recording medium is optional.

In the read-only ROM CD shown in Figure 13, when in R type CD, adopting the groove register system, according to when the reading and recording signal, relation between the characteristic of the detection of servosignal and RF signal, must make the depth of groove in system's Lead-In Area of known dvd standard CD more shallow, thus must the strict characteristic of determining to read signal according to concavo-convex pit.Therefore, when planning the corresponding recording medium of common arrangement, must abide by the recording density of R type CD, reduce the recording density of recording medium.

, be similar under the logging mode of data field for this reason, adopting the signal in data importing district.Thereby in ROM type CD, the identifying code that serves as the reference signal of data field is placed in the data importing district.But,, therefore can distribute the peculiar function of ROM type CD owing to can use high capacity from the zone of this scope.

Because can huge construction program production, so ROM type CD be a kind of fabulous distribution of information instrument.The system that is different from physical criterionization might be proposed as the coded system when the data structure of the above-mentioned information of compression and audio frequency, video etc.That is,, wish physical criterion is defined as data storage location, and provide dirigibility to its application with regard to the physical criterion of the data structure of information recording carrier etc.On the contrary, many users wish to utilize standardization, because can boost productivity thus.Thereby, imagine the method that a kind of record is used to reproduce the decode system of such as content final signal and encoded content, to read the decoding program in the decode system, to utilize the coding/decoding method of indicating in the decode system encoded content is decoded, and use content.

Figure 17 has represented the data structure in the control data band shown in Figure 13.The structure shown in Figure 17 is but that read-only, write-once and rewriting type information recording carrier are common.

In addition, Figure 18 has represented in the read-only information recording carrier, the content of the physical format information shown in Figure 17.

But in read-only, write-once and rewriting type information recording carrier, the information in the physical format information in the information recording carrier of present embodiment all has among Figure 18 the identical information from the 0th byte (writing type and part type)～the 16th byte (BCA descriptor).When this information of replacement, ignore the text or the code data that in the CD manufacturing information, write.

Among Figure 18, BP0～PB31 comprises the common data that uses in the DVD sequence, and BP32～BP2047 is used for the distinctive information of each piece.

The function of each byte location is as described below.

(BP0) write the type and the part version (type) (referring to Figure 19) of standard

Write the type of standard

0100b... the HD-DVD standard of read-only optical disc

These positions will be assigned with, so that the DVD of definition DVD forum issue writes standard.According to these binary digits of following regular allocation.

0000b... the dvd standard of read-only optical disc

0001b... the dvd standard of CD-RW (DVD-RAM)

0010b... the dvd standard of Write-once optical disc (DVD-R)

0011b... the dvd standard of CD-RW (DVD-RW)

0100b... the HD-DVD standard of read-only optical disc

0101b... the HD-DVD standard of CD-RW

Other ... keep

The part version:

0000b... (0.9 of version is used for test to version 0.9, is not suitable for mill run.)

0001b... version 1.0

0100b... (0.9 of version is used for test to version 1.9, is not suitable for mill run.)

0101b... version 2 .0

Other ... keep

(BP1) maximum transfer speed of disc size and CD (referring to Figure 20)

Disc size:

0000b...12 centimetre CD

According to these positions of following regular allocation.

0000b...12 centimetre CD

0001b...8 centimetre CD

Other ... keep

The maximum transfer speed of CD:

(0100b... TBD (back is determined) Mbps)

According to these positions of following regular allocation.

0000b...2.25Mbps

0001b...5.04Mbps

0010b...10.08Mbps

(0100b... TBD (back is determined) Mbps)

1111b... do not specify

Other ... keep

(BP2) compact disk structure (referring to Figure 21)

The number of plies:

00b... individual layer

01b... it is double-deck

Other ... keep

Orbital path: 0b...PTP or SL

1b...OTP

The type of layer:

0100b... according to these positions of following regular allocation.

B3:0b... according to the concavo-convex user data of the format record of Figure 14 A.

1b... according to the concavo-convex user data of the format record of Figure 14 B.

B2:0b... CD does not comprise rewritable user data area.

1b... CD comprises rewritable user data area.

B1:0b... CD does not comprise recordable user data area.

1b... CD comprises recordable user data area.

B0:0b... CD does not comprise concavo-convex user data area.

1b... CD comprises concavo-convex user data area.

(BP3) recording density (referring to Figure 22)

(line density) (data field)

0101b...0.153 micron/position

According to these binary digits of following regular allocation.

0000b...0.267 micron/position

0001b...0.293 micron/position

0010b...0.409～0.435 micron/

0100b...0.280～0.291 micron/

0101b...0.153 micron/position

0100b...0.130～0.140 micron/

Other ... keep

Track density (data field)

0011b...0.40 micron/track (SL CD)

0100b...0.44 micron/track (DL CD)

According to these binary digits of following regular allocation.

0000b...0.74 micron/track

0001b...0.80 micron/track (recordable CD)

0010b...0.615 micron/track

0011b...0.40 micron/track (SL CD)

0100b...0.44 micron/track (DL CD)

0101b...0.34 micron/track

Other ... keep

(BP4～BP15) data field is distributed

But Figure 23 is the synoptic diagram of the content of the information that the data field is distributed in explanation read-only type/write-once type/rewriting type information recording carrier.

(BP16) BCA descriptor (referring to Figure 24)

Whether there is train of impulses cutting area (BCA, burst cuttingarea) on this byte representation CD.Position b6～b0 is configured to " 000 0000b ", and position b7 represents whether BCA exists.

According to following regular allocation these the position:

The BCA mark:

1b...BCA exist.

(BP17～BP31) keep

All bytes are configured to " 00h "

(BP32～BP2047) keep

But Figure 25 has illustrated each regional record data density in the rewriting type information recording carrier of present embodiment.

Can find out from the comparison of Figure 25 and Figure 16, but fully the various sizes with system's Lead-In Area of rewriting type information recording carrier are consistent for the various sizes of system's Lead-In Area of read-only information recording carrier.In addition, though not shown, in the present embodiment, the various sizes of system's Lead-In Area of Write once information recording medium and the consistent size shown in Figure 16 or Figure 25.

But Figure 26 represents the data structure of Lead-In Area of the rewriting type information recording carrier of present embodiment.In Figure 26, in the system's Lead-In Area shown in concavo-convex dimple-shaped is formed in, in its data importing district, form rewritable record mark.

In Figure 26, initial strip comprises concavo-convex data field.The master data that is recorded in the Frame in the initial strip is configured to " 00h ".Buffer strip comprises 32 ECC pieces (1024 sector).The master data that is recorded in as the Frame in the initial strip of physical sector is configured to " 00h ".The control data band comprises concavo-convex data field.The data field comprises concavo-convex control data.

The bonding pad is used to connected system Lead-In Area and data, and this goes into the district.As shown in Figure 27, as an example, the distance between the center line of the initial sector " 02 6C00h " in the center line of the final sector of system's Lead-In Area " 02 6BFFh " and data importing district is configured to 1.4 microns～20.0 microns.

Do not distribute physical sector number or physical address to the bonding pad, the bonding pad does not comprise physical sector number or physical address.

The data segment of protection track ribbon does not comprise data.

The rom test band is used for test mass by disc manufacturer.

Drive (drive) calibration tape and be used to drive test.

Information recording/reproduction device is optimized record condition by write test figure in this zone.

CD ID band in the data importing district comprises activation bit and reserved area.

Activation bit is made up of the corresponding ECC piece in convex ridge track and the grooved tracks, and starts from " 02 CD00h " in the convex ridge track, starts from " 82 CD00h " in grooved tracks.

Figure 28 has represented the data structure of Lead-In Area of the write-once information recording medium of present embodiment.

As shown in Figure 28, the Write once information recording medium of present embodiment has the total control data band of various media in system's Lead-In Area of the concavo-convex pit of record.In addition, write down therein in the data importing district of write-once phenotypic marker, Write once information recording medium has and is used to test the rom test band that writes, drive calibration tape, wherein record is used to adjust identifying code band, CD ID band and the R-physical format information band of the reference signal of the reproducing circuit shown in Figure 14.

The Write once information recording medium of present embodiment is characterised in that and utilizes the level limiter system, and the signal in the detection system Lead-In Area utilizes the signal in PRML system detection data importing district, data field and the data leading-out zone.

Figure 29 has represented to be used for the input/signal evaluation circuit of the signal of playback system Lead-In Area.

Output from four spectrophotometric detector 13a～13d is added, and makes output after the addition by Hi-pass filter 122, after its waveform is proofreaied and correct by pre-equalizer 122, carries out the level amplitude limit by limiter (slicer) 141.

Circuit shown in Figure 29 has following circuit feature.

(1) phaselocked loop (PLL)

Natural frequency under the 4T: ω _n=300 Krads/sec

Dump under the 4T (dumping) rate: δ=0.70

(2) Hi-pass filter (HPF)

Basic fc (3dB)=1.0KHz

(3) pre-equalizer

For example, pre-equalizer is seven grades of equal-ripple filters, and triggering level K1 and cutoff frequency with 9.0 ± 0.3dB are the frequency characteristic of 16.5 ± 0.5MHz.

Except that above-mentioned, the circuit shown in Figure 29 has following circuit feature.

(4) limiter

Load feedback method: fe=5.0KHz

(5) shake

From the frequency range of 1.0KHz～HF, carrying out measuring shake in 1/4th rotations at CD.

Figure 30 is the circuit diagram that is illustrated in the physical circuit that uses in the limiter shown in Figure 29, and it serves as the part of carrying out the level amplitude limit.

In this circuit, utilize comparer to make from the signal binaryization of prefilter (fetch channel 1) output.

Utilize the signal in data importing district, data field and the data leading-out zone of PRML system detection record medium, Figure 31 has represented to detect the circuit diagram of the circuit of this signal.In Figure 31, be similar to the circuit structure shown in Figure 29, be added from the output of four spectrophotometric detectors, make output after the addition by Hi-pass filter 122, after utilizing pre-equalizer 123 correction signals, use the signal waveform of addition output.But as shown in Figure 31, the circuit that output is provided for before the PRML circuit is characterised in that utilizing automatic gain to control (AGC) circuit 124 controls to specified level to the amplitude of reproducing signal.

In the circuit shown in Figure 31, simulating signal becomes digital signal by A/D converter (ADC) circuit conversion.The feature of circuit shown in Figure 31 is summarized as follows.

(1) phaselocked loop (PLL)

Natural frequency under the 4T: ω _n=580 Krads/sec

Dump under the 4T (dumping) rate: δ=1.1

(2) Hi-pass filter (HPF)

Basic fc (3dB)=1.0KHz

(3) pre-equalizer

For example, pre-equalizer is seven grades of equal-ripple filters, and triggering level and cutoff frequency with 9.0 ± 0.3dB are the frequency characteristic of 16.5 ± 0.5MHz.

(4) automatic gain control (AGC)

-3dB closed loop band: 100Hz

(5) analog to digital conversion (ADC)

Relation between the dynamic range of ADC and HF signal

Sampling clock: 72MHz

Resolution: 8, I ₁₁₁Level: 64 ± 5

I ₁₁₁Level: 192 ± 5

(8) balanced device

9 tap transversal filters are used as balanced device.Coefficient is controlled by tapped control.

The resolution of tap coefficient: 7

The resolution of equivalent signal: 7

(9) tapped control

Utilize the tap coefficient of minimum variance (MSE) algorithm computation balanced device.Before calculating tap coefficient, initial value is used as tap coefficient.

Figure 32 has represented the structure of the Viterbi decoder 128 that uses in signal evaluation circuit shown in Figure 31.In the present embodiment, PR (1,2,2,2,1) is used as the PR classification.

From the fetch channel and the ETM code combination of data importing district, data field and data leading-out zone, so that and PR (1,2,2,2,1) passage unanimity.

Figure 33 represents the transition status of first PR passage.

4 previous inputs of Sabcd are abcd, and e/f represents that next input is e, and signal level is f.

As described below, Viterbi decoder is according to the equivalent signal binary data output.

Following computing time the branch metric during t.

BM(t，i)＝(y _t-i) ²

Here, y _tHF signal after the expression equilibrium, i=0,1 ... 8.

The resolution of branch metric is equal to or greater than 10.

As shown in Figure 33, computing time as follows path metric during t.

PM(t，S0000)＝min{PM(t-1，S0000)+BM(t，0)，PM(t-1，S1000)+BM(t，1)}

PM(t，S0001)＝min{PM(t-1，S0000)+BM(t，1)，PM(t-1，S1000)+BM(t，2)}

PM(t，S0011)＝min{PM(t-1，S0001)+BM(t，3)，PM(t-1，S1001)+BM(t，4)}

PM(t，S0110)＝PM(t-1，S0011)+BM(t，4)

PM(t，S0111)＝PM(t-1，S0011)+BM(t，5)

PM(t，S1000)＝PM(t-1，S1100)+BM(t，3)

PM(t，S1001)＝PM(t-1，11000)+BM(t，4)

PM(t，S0110)＝PM(t-1，S0011)+BM(t，4)

PM(t，S1100)＝min{PM(t-1，S0110)+BM(t，4)，PM(t-1，S1110)+BM(t，5)}

PM(t，S1110)＝min{PM(t-1，S0111)+BM(t，6)，PM(t-1，S1111)+BM(t，7)}

PM(t，S1111)＝min{PM(t-1，S0111)+BM(t，7)，PM(t-1，S1111)+BM(t，8)}

The resolution of path metric is equal to or greater than 11.

Addition-comparison-alternative pack (corresponding to the ML demoder shown in Fig. 7) calculates new path metric, and new path metric is offered the path metric storer, and selecting to offer path memory.

Select 0=0

((PM (t-1, S0000)+situation of BM (t, 0)＜PM (t-1, S1000)+BM (t, 1)))

Select 0=1 (other situation outside above-mentioned)

Select 1=0

((PM (t-1, S0000)+situation of BM (t, 1)＜PM (t-1, S1000)+BM (t, 2)))

Select 1=1 (other situation outside above-mentioned)

Select 2=0

((PM (t-1, S0001)+situation of BM (t, 3)＜PM (t-1, S1001)+BM (t, 4)))

Select 2=1 (other situation outside above-mentioned)

Select 3=0

((PM (t-1, S0110)+situation of BM (t, 4)＜PM (t-1, S1110)+BM (t, 5)))

Select 3=1 (other situation outside above-mentioned)

Select 4=0

((PM (t-1, S0111)+situation of BM (t, 6)＜PM (t-1, S1111)+BM (t, 7)))

Select 4=1 (other situation outside above-mentioned)

Select 5=0

((PM (t-1, S0111)+situation of BM (t, 7)＜PM (t-1, S1111)+BM (t, 8)))

Select 5=1 (other situation outside above-mentioned)

Figure 34 has represented an example of path memory.Path memory has, for example 20 storage unit.Figure 35 has represented the structure of I/O and path memory cell.As shown in Figure 36, finally path memory cell is only exported a signal as binary data from output terminal 0.

As mentioned above, (utilize the laser beam of 405 nano wave lengths with regard to CD of the present invention, can be from its information reproduction, utilization has the laser beam of identical wavelength, recorded information thereon), with compact disk equipment of the present invention (it can be on CD recorded information, and can be) from optical disc replay information, in the CD of any type, it is read-only optical disc, only record once (write-once type) CD and recording/reproducing optical disk (RAM CD) one of any in, before birefringent level reaches pre-determined amount, the level limiter system can reproducing signal, and is comprising that its level reduces in the birefringent CD of signal intensity when with level limiter system reproducing signal, can in than the suitable error rate scope that goes out the high grade of rate in the level limiter system, utilize PRML system reproducing signal.In addition,, allow reduction, increase tolerance limit with respect to signal intensity by adopting the PRML system.

In addition, with regard to the birefringent level in the CD that is included in respective type, when this level allowed to obtain reproducing signal in predetermined error rate scope, this level was configured to:

(standard ECMA-267 is 100 nanometers in p15) at the dvd standard read-only optical disc;

(standard ECMA-279 is 100 nanometers in p16) at the DVD-R that can only write down primary information;

(standard ECMA-272 is 60 nanometers in p13) at DVD-RAM that can rewrite information.

The present invention is in no way limited to above-mentioned each embodiment, when imbody is of the present invention, in the scope that does not break away from claimed essence of the present invention, can make various modifications and variations.In addition, as possible, can come the imbody respective embodiments, can obtain combined effect in this case by mutual combination.

To one skilled in the art, additional advantages and modifications are conspicuous.So the present invention is not limited to detail and the exemplary embodiments representing and illustrate here.Therefore, not breaking away from by accessory claim and being equal under the situation of spirit or scope of the general inventive principle that limits, can make various modifications.

Claims (12)

1, a kind of CD (1), it is characterized in that comprising by the molded molded matrix (1a that forms of injection moulding, 1b), and has a transfer information flag thereon, on described CD, form and utilize 600 nanometers or the laser beam of small wavelength more, can only write down the recording film (2) of primary information, and can be on described CD recorded information and from described optical disc replay information, perhaps on described CD, form reflectance coating, so that from optical disc replay information, wherein when utilizing twice when measuring, the value of the birefringence component in the whole zone of CD is ± 60 nanometers or littler.

2,, it is characterized in that when using the PRML signal Processing to come information reproduction when utilizing twice when measuring, the value of the birefringence component in the whole zone of CD is ± 85 nanometers or littler according to the described CD of claim 1.

3,, it is characterized in that the value of the birefringence component of CD is ± 75 nanometers or littler when utilizing twice when measuring according to the described CD of claim 2.

4, a kind of compact disk equipment (20), described compact disk equipment can be in the last recorded information of CD (1) and from CD (1) information reproduction, on described CD (1), be formed with utilize 600 nanometers or more small wavelength laser beam, can only write down the recording film (2) of primary information, perhaps described compact disk equipment can form the optical disc replay information of reflectance coating from it, it is characterized in that the value of the birefringence component in the whole zone of CD is ± 60 nanometers or littler when utilizing twice when measuring.

5,, it is characterized in that when using the PRML signal Processing to come information reproduction when utilizing twice when measuring, the value of the birefringence component in the whole zone of CD is ± 85 nanometers or littler according to the described compact disk equipment of claim 4.

6, the compact disk equipment of stating according to claim 5 is characterized in that the value of the birefringence component of CD is ± 75 nanometers or littler when utilizing twice when measuring.

7, a kind of CD (1), it is characterized in that comprising by the molded molded matrix that forms of injection moulding (1a, 1b), and has a transfer information flag thereon, on described CD, form the recording film (2) that can write down with erasure information, and utilize 600 nanometers or the laser beam of small wavelength more, can be on described CD recorded information and from described optical disc replay information, wherein when utilizing twice when measuring, the value of the birefringence component in the whole zone of CD is ± 40 nanometers or littler.

8,, it is characterized in that when using the PRML signal Processing to come information reproduction when utilizing twice when measuring, the value of the birefringence component in the whole zone of CD is ± 70 nanometers or littler according to the described CD of claim 7.

9,, it is characterized in that the value of the birefringence component of CD is ± 55 nanometers or littler when utilizing twice when measuring according to the described CD of claim 8.

10, a kind of compact disk equipment (20), described compact disk equipment can be in the last recorded information of CD (1) and from CD (1) information reproduction, be formed with on the described CD (1) and can utilize 600 nanometers or more the laser beam record of small wavelength and the recording film (2) of erasure information, it is characterized in that the value of the birefringence component in the whole zone of CD is ± 40 nanometers or littler when utilizing twice when measuring.

11,, it is characterized in that when using the PRML signal Processing to come information reproduction when utilizing twice when measuring, the value of the birefringence component in the whole zone of CD is ± 70 nanometers or littler according to the described compact disk equipment of claim 10.

12, the compact disk equipment of stating according to claim 11 is characterized in that the value of the birefringence component of CD is ± 55 nanometers or littler when utilizing twice when measuring.

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